An expanding job description for the Zinc finger transcriptional repressor Blimp1/Prdm1 in the developing mouse embryo

The zinc finger transcriptional repressor B-lymphocyte-induced maturation protein 1 (Blimp1), encoded by the Prdm1 gene, originally cloned as negative regulator of β-interferon gene expression and subsequently identified as a master regulator of plasma cell terminal differentiation, governs cell fate decisions in the developing embryo and adult tissues. In the early embryo, Blimp1 is required to specify the primordial germ cell lineage, and embryos die at midgestation due to an essential requirement in the placenta. Using conditional deletion experiments we have found that Blimp1 activities are essential for morphogenesis of the pharynx, forelimbs and heart. In addition Blimp1 regulates the developmental switch responsible for post-natal reprogramming of the intestinal epithelium. Most recently we have found that Blimp1 identifies a rare population of luminal progenitors in the mammary gland that are essential for morphogenesis and organ homeostasis.